1. Technical Field of the Invention
The present invention relates to a sprinkler head to be installed in a building and actuated in case of fire to spread a fire-extinguishing liquid. The present invention also relates to a sprinkler head cover to be installed in the same sprinkler head.
2. Description of Related Art
A sprinkler head installed in a ceiling or a wall of a building interior is coupled to a water supply piping, in which a nozzle is closed by a valve within the sprinkler head. The valve is supported by a heat-sensitive operating section in which is incorporated a heat-sensitive element, and in operation, the heat-sensitive element can sense the heat from fire and trigger the heat-sensitive operating section to be actuated for opening the valve.
When the valve is open, a fire-extinguishing liquid within the nozzle is released, and the fire-extinguishing liquid would impinge upon a deflector disposed ahead of the nozzle and then spread all around to mitigate or extinguish fire.
In connection with the sprinkler head, a sprinkler head cover has been provided in order to cover the sprinkler head because the sprinkler head is not desirable from the viewpoint of design.
The sprinkler head cover comprises a housing attached externally to the sprinkler head and a cover plate for covering the sprinkler head, both of which are connected to each other by means of a low melting point alloy.
In case of fire, hot air stream from flames and smoke as well as heat absorbed by the cover plate of the sprinkler head cover would melt the low melting point alloy to thereby disengage the cover plate from the housing to permit the cover plate to drop down.
Subsequently, the sprinkler head disposed inside the housing would be actuated with heat from the fire so as to spread the fire-extinguishing liquid.
The sprinkler head provided with the sprinkler head cover includes, for example, one having a disc-like cover plate (see, for example, U.S. Pat. No. 5,372,203) and another having a bowl-like cover plate (see, for example, U.S. Pat. No. 5,072,792).